Molecular emm genotyping and antibiotic susceptibility of Streptococcus dysgalactiae subsp. equisimilis isolated from invasive and non-invasive infections

Abstract

To analyse the characteristics of infections caused by Streptococcus dysgalactiae subsp. equisimilis, clinical isolates (n5145) were collected at 11 medical institutions between September 2003 and October 2005. These isolates belonged to Lancefield group A (n55), group C (n518) or group G (n5122). Among all isolates, 42 strains were isolated from sterile samples such as blood, synovial fluid and tissue specimens from patients who were mostly over 50 years with invasive infections, and included seven cases of streptococcal toxic shock syndrome and necrotizing fasciitis. In contrast, the remaining 103 were isolated mainly from patients of all age groups with non-invasive infections such as pharyngotonsillitis. These isolates were classified into 25 types based on emm genotyping. A significant difference in emm types was observed between isolates from invasive and non-invasive infections (P,0.001): stG485, stG6792 and stG2078 predominated among isolates from invasive infections. A phylogenetic tree of complete open reading frames of emm genes in this organism showed high homology with those of Streptococcus pyogenes, but not with those of other streptococci. The presence of five different clones was estimated based on DNA profiles of isolates from invasive infections obtained by PFGE. Genes for resistance to macrolides [erm(A), three isolates; erm(B), five isolates; mef(A), seven isolates] and levofloxacin (mutations in gyrA and parC, four isolates) were identified in this organism. These results suggest the need for further nationwide surveillance of invasive infections caused by S. dysgalactiae subsp. equisimilis. INTRODUCTIONMost b-haemolytic streptococcal pathogens isolated from humans are identified as Streptococcus pyogenes (group A streptococci; GAS), Streptococcus agalactiae (group B streptococci; GBS), Streptococcus dysgalactiae subsp. equisimilis and species of the anginosus group that belong to Lancefield groups A, B, C, G or F (Facklam, 2002;Ruoff et al., 2003). In contrast to GAS and GBS, which are known to cause serious and systemic invasive infections, streptococci with Lancefield group C or G antigens were long considered to be commensal organisms that only rarely caused invasive infections as opportunistic pathogens.In 1996, S. dysgalactiae subsp. equisimilis was proposed as a new streptococcal taxon (Vandamme et al., 1996). Although rare, S. dysgalactiae subsp. equisimilis strains having group A antigen rather than group C or G antigen have also been reported (Bert & Lambert-Zechovsky, 1997;Brandt et al., 1999;Katsukawa et al., 2002 Notably, S. dysgalactiae subsp. equisimilis possesses many virulence factors shared with GAS, such as M protein (Fischetti, 1989; Schnitzler et al., 1995), streptolysin O (Gerlach et al., 1993Okumura et al., 1994), streptolysin S (Humar et al., 2002 and streptokinase (Walter et al., 1989;Ikebe et al., 2004). It has been suggested that these factors were transmitted from GAS to this species (Kalia et al., 2001).In the present report, we have described S. dysgalactiae ...

Group C Streptococcus dysgalactiae subsp. equisimilis in south-east Brazil: genetic diversity, resistance profile and the first report of human and equine isolates belonging to the same multilocus sequence typing lineage

“…equisimilis (SDSE) has increasingly been recognized as the aetiological agent of several human invasive infections worldwide (Bruun et al, 2013;Sunaoshi et al, 2010;Takahashi et al, 2010Takahashi et al, , 2011Tsai et al, 2014). SDSE isolates are frequently classified as Lancefield group C or G. Comparative genomic analyses revealed that several commonly found group A streptococci virulence factors have also been detected in SDSE isolates, including C5a peptidase, M protein, glyceraldehyde 3-phosphate dehydrogenase, hyaluronidase, streptokinase, streptolysin O and streptolysin S, amongst others (Reissmann et al, 2012;Sunaoshi et al, 2010;Suzuki et al, 2011;Watanabe et al, 2013). Consequently, human infections related to SDSE resemble those associated with group A streptococci .…”

“…Similar to group A streptococci, SDSE has also been linked to post-infectious sequelae such as glomerulonephritis and rheumatic fever (Takahashi et al, 2011). Although SDSE isolates remain susceptible to penicillin, different studies have reported an increased prevalence of antimicrobial resistance to non-b-lactam agents clinically employed for streptococcal infections, including tetracycline, clindamycin and erythromycin (Kim & Uh, 2004;Rato et al, 2010;Sunaoshi et al, 2010;Takahashi et al, 2011).It is well known that SDSE isolates can also be associated with equine and other animal diseases, including strangles, Abbreviations: MLST, multilocus sequence typing; SpP, sporadic pattern; SDSE, Streptococcus dysgalactiae subsp. equisimilis; UPGMA, unweighted pair-group method using arithmetic averages.…”

Endocarditis por Streptococcus equi subsp. zooepidemicus

“…No hay casos documentados como el que presentamos de endocarditis por este patógeno. Con respecto al tratamiento, Streptococcus de los grupos C y G son sensibles a betalactámicos y la penicilina como en nuestro caso se considera el fármaco de elección 12 . La cefalosporinas de tercera generación son altamente activas y por tanto frecuentemente utilizadas.…”

Eritrodermia con bacteriemia por Streptococcus dysgalactiae subespecie equisimilis en un paciente pediátrico: reporte de un caso y revisión de la literatura

“…En un estudio en Japón, se encontraron diferencias significativas en relación a la genotipificación emm, al comparar los agentes aislados de pacientes con enfermedad invasora (stG485, stG6792 y stG2078) versus no invasora 11 .…”